Gracie's Hack... DR650 sidewalk chalk build

[CAVEboy]

**Edited** to include new upper subframe. I decided to leave pics of the old one for reference. New pictures in post below

I've never built a sidecar before and am going to need some advice and info. I got most of the subframe mocked up and thought I'd start a thread to get some feedback/criticism. The blue tape is where further bracing will be added. The real questions I have are in regards to the strength of my mounting points. I'm confident I can build a nice frame and car, but if my mounts aren't strong enough and in a decent location for geometry it will all be wasted. Please tell me if you think my frame mounts (specifically my uppers) are going to last in the long run and not ruin my bikes frame.

This is Gracie and she is moping while she thinks about the wind in her face and the freedom of the moto...



I use sidewalk chalk for fabrication all the time. This is my idea of the car frame (will likely change/refine). I was originally thinking 2'x4' for the frame, but am worried it may be too narrow. I want narrow for offroad riding, but not too narrow negating the utility. It will also be built from 1.75" .120 wall tubing and will basically be a flatbed that a car body can be bolted to for Gracie. Construction of the frame seems easy to me, I'm just trying to hash out the size before bending the tube. I'm thinking I may keep it 2x4' and just space it away from the bike a little to leave room for my upper control arms without compromising car space.



The swing arm and tire/wheel combo are in process. I was planning on building a custom swing arm and machining and axle and such for a spare DR wheel I have (would be nice to have matching wheels), but am now thinking I may cheap out and be lazy with a trailer hub/wheel combo swing arm. Depending how I like it I may spring for air suspension (many options here) or keep it simple with a moto shock. Chalk drawing hasn't yet accounted for wheel placement and swing arm dimensions.



I am so close to bending up the frame and am having a hard time waiting for feedback so please give me your thoughts and advice. I will try to curb my stubborn attitude to listen to experience.

I would love to see some links to photos of trailer hub swing arms. Maybe even a few custom two-sided swing arm setups. I really don't mind having a swing arm visible from the side of the car.

[TouringDave]

This is going to be good!

[ClearwaterBMW]

wow...
looking forward to this one
thanks for taking us along on the ride

[Pete-NZ]

This thread will become a regular stop over...
With the the way you have made the sub frame
it would have been easy to move the rear mount
fearther rear-wards...wider spaceing would have
given more ridgillity in the mounts..
Thats possably a mistake I made with my XR build...

[Salsa]

Structurally it should work fine. The three load points to the external world are triangulated just fine.

Don

[DRONE]

Hey guys--unfortunately, this is starting to look suspiciously like a BUILD thread. I'm notifying AceRph. Build threads are not allowed here anymore.

[SYDADVGS]

Originally Posted by DRONE

Hey guys--unfortunately, this is starting to look suspiciously like a BUILD thread. I'm notifying AceRph. Build threads are not allowed here anymore.

I think the OP is seeking sidecar specific advice which he may not get in the build thread

[CAVEboy]

Originally Posted by SYDADVGS

I think the OP is seeking sidecar specific advice which he may not get in the build thread

Agreed! Can we move it to the build thread when I don't need help anymore??

Anything to say about the car frame size? What dimensions might yours have? Info and/or pics on swing arms? I am searching and reading plenty in conjunction with these questions, just looking for some specific info that is easier to ask about directly.

[NortwestRider]

I didn't get my TRIANGLE right when I built mine and it works GREAT,lots of offroad and it's a heavy car and it's holding up great.NEXT build I will get it right but for now it's working great.

[TouringDave]

Hey! I just realised something. You're mounting the sidecar on the left hand side!

Oh, and a few pics.

Single sided swingarm detail



Sidecar Chassis detail:

[RedMenace]

it looks like you are planning a Left side mount?

[CAVEboy]

Yep, left side mount. That's not a problem right? I know that right sided mounts are more common and "correct" for the states, but I like the fit and function of the left side.

[TouringDave]

Originally Posted by CAVEboy

Yep, left side mount. That's not a problem right? I know that right sided mounts are more common and "correct" for the states, but I like the fit and function of the left side.

What's the legality of that caveboy?

Here in Aus. it's like a left and right hand drive car.

[RedMenace]

Originally Posted by CAVEboy

Yep, left side mount. That's not a problem right? I know that right sided mounts are more common and "correct" for the states, but I like the fit and function of the left side.

not a problem if you don't mind not being able to see around traffic without putting your sidecar into the opposing lane. If it is strictly an offroad rig it won't make any difference. If it will be on the street it is a bad idea unless there is a compelling functional reason to set it up that way. The only thing that comes to mind is rural mail delivery

[CAVEboy]

Ok, turns out I'm not as stubborn as I thought and I'm easily persuaded to change plans and priorities. I didn't want to put the car on the right because I had a stronger and much much easier mounting system on the left side. After pondering the traffic topic I decided to get my head in the game and make it work. Here is what I came up with. What do you think? I also spaced out the lower mounts a little more as mentioned above. Thanks for the comments... please keep them coming.

Lower sub frame is 1.75" .120 wall and the upper 1.25" .120 tubing. Lower rear mount will be braced but didn't get to that today.



She is ready! Turns out I don't work fast enough for her. Frame is 1.75" .120 tubing. Track width should work out to around 44-45". Good??



This is the mount in question. It is behind the oil cooler and only uses that one oil cooler bolt. The bars in the first picture that tie the whole "upper" frame together are only there to give this mount longitudinal and vertical support. I believe it will be strong enough, but don't really know about the forces involved with moderate offroading of a sidecar. Please weigh in... especially if you are a sidecar builder!